Filler cap. Front. A cover that prevents foreign debris from entering the container. Included in Reservoir assembly. Washer Fluid Reservoir Cap. Windshield Wiper Arm Cap. WSWA SOLV CNTNR. Engine Coolant. Filler neck. Washer Fluid. Windshield Wiper Arm. Included with: Filler tube, Reservoir assembly, Reservoir hose, Washer Reservoir.